Help me with hard drives

[Cyberdan3]

I bought a Sony Viao, and it has a 120 GB hard drive. In my C: drive, it says it had 19 GB or space, and the D: drive has 99GB. All the Sony programs loaded into the computer almoost filled up my C: drive already. I had to start saving everything to the D drive. I know yoyu ca go into disk management and change drive letters, but can you switch my C and D drive so that the C drive has 99GB of disk space, and the D drive can be my sony drive for backup?? I say to change c drive but it says I can't. I went to Circuit City and they don't know shit about it. I was hoping you guys could help. If you know how to do it, please reply. Thanks I have to go to Christmas mass now so I hope you can help me. By the way, I took all my game files and put them in D so I am ready to swap drives.

[Disk_Contented]

Changing the partitions around is not an option.
The only suggestions i can make are to:
a) Use Partition magic or similar to resize the partitions. Just back up first!
B) Uninstall some progs from drive C: and reinstall them in D:
In future, install new programs to D: (large ones anyway)
The first option is probably the best as your partitions are badly balanced.