That seems to be 1.6 Gigs, give it time, it'll work
it'll just be slow, but i'll work.
That is a known bug with Win2k and WinXP. Disk Cleanup is freezing because it is searching for old files that should be compressed but that aren't.
Try this...
1. Run Regedit
2. Click on My Computer (in Regedit)
3. Go to Edit -> Find
4. Type in "Compress Old" (less the quotation marks)
5. Click Find Next
6. Regedit will find the Compress Old Files key
7. Press Delete (and click 'yes' to the 'are you sure?' prompt)
8. Reboot
Disk Cleanup shoudl now run like a breeze.