I bet full of spyware and other system junk both in the system and registry. Its time for a larger hard drive do a backup and or reload windows on the old HD to get a clean install and get rid of all that junk.
Whenever i do this the contact list takes long to load. I notice my whole computer has been slowing down also. Tasks are taking long to complete and all.
I scanned for viruses using NAV and found 1 adware file.
I have like 4 GB (out of 53GB) of space left.
I reinstalled Messenger but the same problem occurred again.
Im using XP Home, P4, 256 kb of memory.

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