Locked out and Missing 'My Computer and Control Panel'

I had mistakingly installed something from the Windows XP Magazine's disc
namely 'Tweak XP-Pro'.

After running the program and at first using light 'tweaks' I noticed my
Firewall was disabled. I then noticed I could not use my wireless internet
connection and that there was no access to Control Panel or My Computer.
I have tried to go to security settings and get this messge.

'Thsi operation has been cancelled due to restrictions in effect on this
computer. Please contact your system administrator'

I have also very recently cleaned up my drive and have cleared the restore
points so I cant go back. I have also tried to restore the windows defaults
throught the above utilitu but this has not restore or given me access to any
of the standard features.

What can I do?

Thanks,

Keith