(my friends tell me, that this picture is a 'close' match to reality)
then I try to calm down by listening to some Music ,
maybe relax and try to get a laugh from some computer/network jokes
and then I run through the list of possible causes:

A word of warning: before making serious changes to a system (like: upgrading the operating system),
please make sure that you have a good Backup (and keep on later making Backup's ) !

which connector to use on Combo / Multi-Connector Board ?
Testing Connection using 'NET DIAG'
Testing Connection using TCP/IP (updated Sept. 16, 2001 )
Ping works only in ONE direction (created April.8,2001)
FastEthernet and Hubs : Auto Select "Media speed"/"Duplex mode" failing (created April 13,2001)
Network card Diagnostics (created Feb.6,99)
Device Manager (created Feb.12,99)
Device Manager Codes (created Feb.12,99)
What is my IP/Ethernet Address ?
Choosing the proper protocol for MS PC-to-PC: NetBEUI
The IPX Frame Trap
IPX:"Error loading protocol 0, error 254" (created July 11,98)
Netware Compatible shell is not available (created Sept.21,98)
System process - Lost delayed write data (created Sept.22,98)
Error Mapping a Drive (updated July 12,98)
Error: "The computer or sharename could not be found"
File and Print Sharing Not Available (Created Oct.9,1999)
I forgot my Password (Created Dec.13,97)
Display Login-Box without the Name of the last User (updated: Oct 21,2000)
Cannot get on Bootup the Logon Window (created Sept.19,98)
Dialup-Networking does NOT save the Password (updated Aug. 17,99)
NT DUN/RAS connection terminating quickly/unpredictable(created Aug.21,99)
Connecting to the Internet makes the local Intranet/WAN unavailable (created March 24,2001)
Trouble Shooting a DCC Connection (created Feb.14,2000)
"Connect to" dialog-box on LAN-usage (created Mar.29,98)
Error Browsing/Mapping a Drive on an NT System (created Nov.2,97)
NT4-Sharenames NOT visible in Windows 95/98 (created Jan.22,2000)
Error:"Unable to browse the Network" ( Updated Jan 23,,99)
Error: "... is not accessible / The device is not ready" (created Aug. 2,2000)
Error: "Permanent connection not available" (updated May 1, 2001)
Error: "the network path was not found" (updated May 1, 2001 )
Error:"Invalid Local Drive"
Unable to Browse the NT Server (created June 6,98)
Windows95 &Windows98 systems do NOT see each other (updated Jan.23,99)
Windows98 is not able to connect to SAMBA (created Sept.26,98)
Windows95 as a Router (created June 28,98)
Error:"The Network is not accessible" (Updated Mar.7,98)
Error:"The request resource is in use" (created Feb.18,2001)
Error: "the network name cannot be found" (created Dec.9,2001)
Error: "Access is denied" (created Dec.9,2001)
Error:"There is not enough storage to complete this operation" created : Jan. 6,2001
"It takes a long time to shutdown" (created may 30,98)
Windows98 does NOT shutdown (created Dec. 4,1999)
Tab: "Access Control" is missing (Created Nov.13,97)
Buttons/Menus for File Sharing missing (created Feb.8,99)
Is the Network-Connection "healthy" ? (Created Dec.7,97)
The Network is slow ! (created Oct.31,97)
Speed Differences: fast in one direction, slow in the other (created Aug.8,99)
Networks require a Common Ground (created Oct.11,97)
Checklist: PC not showing up in Network Neighborhood (updated Nov.3,97)
Network Client-Cache causing data-corruption ? (updated May 1,98)
Possible Data Corruption by Microsoft Network Client (created May 1,98)
Possible Database File Damage when Data is appended (Updated: Oct. 8,2000)
Windows98 takes a long time to boot (Created July 15,98)
Corruption of TCP/IP information in the NT4 Registry (created: jan.9,99)
NT4 - TCP/IP error: "Registry service subkey already exists"
NT4 - TCP/IP error: "Unable to remove name space provider"
Encryption Conflict between IE5.5 and SP6a (created Dec. 2, 2000)
ICS error: "Unable to connect because of a configuration error" (created July 28,2001)
ADSL via Network Card : Problems with ADSL Connection (Delays) (created Nov.1,2001)

Using Telnet to delete POP3 e-mail (created Feb.20,2000)
Getting Auto-Disconnected from NT4 (created Feb.22,2000)
Problems browsing the Web (created June 24,2000)
What is the Windows Version ? (created May 24,2001)

Most troube-shooting under Windows requires loading/unloading of devices or
changing some of the parameters of devices, which is then causing a lot of rebooting,
sometimes you are trouble-shooting hangup's, and then a very special keyboard
could be helpful:

Just joking.......

And if NOTHING can fix it, it could be a corruption, then:
Delete ALL network items and re-install (created July 8,98)

Since in my area cable-modems are not available, I have no experience with them, so please check for questions on Cable-Modems:

www.cablemodemhelp.com