Windows 7: multiple operating systems

hi how many operating systems can i run. at present i have windows 7 ultimate 32 bit running on my d/partition its 200gb in size. i also have windows xp sp3 home edition on c/drive.i also have E/partition on my pc its 220gb in size. my pc is capable of running windows 7 ultimate 64bit. i have 3GB memory [ram] my pc has amd sempron[tm]processor 3000 plus 1.8ghz. ive heard of a free program called VMware does anyone else have multiple operating systems running on there desktop pcs thank you

Each OS will need a partition, as you say,you have three partitions, OS = three.

yes thats right i have c/drive windows xp sp3 is on it it is 20GB in size with 12GB left.on my D/partition im running windows 7 ultimate 32 bit.i purchased windows 7 ultimate 64bit last week im going too run this on my E/partion and do a clean install would this be possible too do this any help much appreciated

If your PC is 64bit, yes.

ok thanks for all your help i will install windows 7 ultimate 64bit on my E/partition

You are welcome.

VMWare needs a good amount of ram to run sufficiently. I don't know exactly what a good amount of ram is or should I say the least you can get by with but 3gb seems to be cutting it a little slim. You might hang on a lot of operations.

Rather than VMWare I would recommend Virtual Box. I run Ubuntu in vBox on a 3GB system. I allocated 1 GB to vBox. Runs really well and practically as fast as my native Windows 7.

The big advantage is that I can run Ubuntu and Windows 7 in paralell and switch back and forth without doing anything special - with the guest additions activated.

As an example, this is a snip of part of the Ubuntu full screen window that I took with a Windows 7 snipping tool:

hi whs thanks for reply is virtual box a freeware program is there tutorials on this program

Are those driver letters fixed or does the OS you are booted into always show as C as it should?

If not, you apparently didn't boot Windows 7 to install it but ran it from XP which was already holding C and thus blocked it's use by Windows 7.

In the future, always boot the installer to install an OS so when booted into it on a multi-boot it will show as C. You must do this anyway to install a different bit-version, of course.