Do you have a fixed paging file present or a static one?
If you have a fixed paging file set, it is possible that you could use the HDD for some more time.
Though, it would be slow in responding and functioning.
Apart from that, i have seen systems with 50+MB of temp internet files.
Get rid of those.
Burn your important stuff into DVD's or CDs.
Zip files which you will not use for a long time.
Delete all unwanted content, remove replicated files, empty your recycle bin and then defragment your comp.
This should create enough space for you to work with for sometime
HOWEVER, if you do plan to game
,which i think you would, then your system performance will definately be hit. Which means its time to get a new HDD.