How much space is enough for c drive on my pc?

presently I have 80 gb hard disk with win 98se in my c drive of 20gb and it is only 2.40 gb used. I am upgrading to intel dual core with 1 gb ram %26 will work with win xp or vista. i intend to not download any thing other than windows on c drive so i don't want to keep much space for c drive. pl also guide is there some program which automatically downloaded to c drive %26 secondly is it necessary to keep antivirus on the same drive where window is loaded.

How much space is enough for c drive on my pc?norton 360

12-15Gb would be okay for xp because, some of the rar,zip files you open frequently will be stored in c: , also many game saves sit on c: , some of the installer packages get automatically stored on to c: , if you run antivirus like KAV it uses c: to store the update info and its database even if you have installed it on a different drive, this tends to get bulky.

if you can clean it manually 10Gb partion for c: is enough.

How much space is enough for c drive on my pc?photoshop

Left over 20Gb for it. And it is better to install AV to the C drive with os.
Hi. A 20 GB partition for the system files is probably overkill. Yes, you will need to scan the Windows files for malware.
If your going to a 64 bit OS with the upgrades 20gb isn't enough for Vista. You'll have plenty of room with XP x64 though. and I would recommend you ''ghost'' your current drive to a SATA hard drive.
40gb for c and another 40 for d is good...
You have plenty of room for XP and Vista, on your C: drive. You can install programs on any HD you choose to.
10GB enough for XP

And

20GB for VISTA