Have you tried using the compatibility feature for the Autocad installer file. You can try activating Win2k compatibility for the installer file (or any earlier version of windows for that matter).
USB can provide +5V. Check the following page for the pinout
http://www.networktechinc.com/technote.html
Check this site for more information on USB
http://www.usb.org/developers/docs.html
I can't remember if this works in Win98 but you can try.
Go to Start>Run and type "msconfig"
If it runs you will get a window showing your startup settings. Uncheck any options that you don't want.
Open up the registry editor by choosing :
Start>Run
then type "regedit" (without the quotes)
Once regedit is open browse to the following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Here you will see entries programs that are run on every start up. Delete...