[Felix The Assassin]

Win98SE, uhm..... Micro$haft posted the product cycle last year, and 98 support was dropped back in the Fall.

From Where, and What was downloaded???

Norton??? Full deal??? Why????
The home user has only a very small need for Norton. Anti-V and Firewall, the rest is hmm. Let me say, global iconization for using system resources per the instruction of the algorithm to allow no functional input by the user to accommodate a better never complaining system.
Honestly, to the untrained, utilities will create way more issues than they will ever fix.

Back to your problem. Reboot in safe mode, and attempt to un-install whatever it was that was installed, hopefully the file name and date, along with the web site is on a scratch pad next to the machine. This way, when one does have problems, they have a reference right there to help fix it.
Honestly I have not touched a rig with 98 in at the least 4 years. Is there a restore point on there soewhere.

From a hardware standpoint you are out of the woods. You are facing a software issue. The clicking sound emitted when the mouse is moved is due to the driver database failing to be installed.
Without a restore point, or no info on what was installed, the only fix may be a complete OS rebuild. And if in fact you were mislead to a "bad " site, the only fix is a complete fresh start. But, since you are PC savvy, you have all of your most importatnt items on disk right? You know, e-mails, and web sites, last weekends English project, and your history report. Anything of more importance should be on disk. While your at it, there are some newer user friendly OS' available.

Good luck