Hi,
It has not been cleaned up for 4 years
This alone is a very good reason for a re-install :-)
Honestly, re-install Windows, dump IE for Firefox (also quite crappy, but the least pain of all browsers imho) and get another 512 MB of Ram (5-10 Euro on Ebay for this machine).
Btw: Celerons are a p*** i* t** a*** - crippled, half defect Intel CPUs sold for profit instead of salvaging...
Kind regards,
Peter