Trojan Horse removal and settings issues

[cbjen]

Hello,
My computer was infected with "trojan horse". I run on Windows XP. I have noticed for a few weeks now that I had some type of trojan, as [censored] sites would pop up when I would click my "start" button or "my controls". Norton Anti-virus picked it up yesterday but could not repair it. The virus was in WINNT\system32\sysreg.exe. The file(?) was quarantined by Norton.
I went into regedit and removed 2 keys with "sysreg" in them. Both had NortonAntiVirus-somethingorother prefixes. I deleted them assuming that the prefix was because the trojan had been quarantined by Norton.
BTW, this was NOT done in safe-mode.
Now....I have several problems...
Norton is not running correctly... It will not scan, auto-protect, script-block or autoscan. They simply say "error". I tried to get support from Symantec, but as soon as I click..."Run automated support assistant"....I get a Browser error... "The page cannot be displayed
The page you are looking for is currently unavailable. The Web site might be experiencing technical difficulties, or you may need to adjust your browser settings. ". I can browse some sites, but not others. I've fiddled with my setting in an effort to repair this problem, but they all seem correct. I don't think the problem is on Symatec's end because I got the same browser error trying to open AOL webmail.

Can someone help me with my browser settings and help to to determine if this Trojan is gone. Also...if there is some way to repair NortonAntiVirus.

Thank you,
Jennifer