The malware has put administrator restrictions on your pc. Although the system may be cleaned the restrictions remain.Click here
to start downloading a tweak from Kellys korner to undo the restriction.Ref: http://www.kellys-korner-xp.com/xp_tweaks.htm
Line 146, Right hand side, Undo option
Download to your desktop, once download is complete double click to run. When prompted allow the registry merge.
I would also run Malwarebytes Anti-Malware (free) as a precautionary measure. Most AV programs will disinfect a system but leave remnants of the malware behind, making the PC prone to further attack. Malwarebytes is very good at cleaning up.