Slow, Memory keeps getting eaten up for no reason... please help?

I'm going to be honest and tell you that this laptop is pretty old. It used to be my father's and knowing his knack for making videos, downloading programs, and with my own combination of using it when I was younger with gaming has made it slow. I'm hoping we can "save" this old laptop to help me with college, as I have no money to buy a new one. :(

Whenever I browse on my computer its slow, I had it cleaned awhile ago on this site for viruses, since I haven't used it at all since then I don't think that's the source of the problem, but I'll post later on the security forums to have it checked out again. :)

My computer keeps eating up memory, it jumps from telling me I have 47 GBs left to 36 GBs and I've tried everything from running a disk check to deleting temporary files and useless programs and it still seems to be eating up memory usage for some weird reason.

The Laptop I am on has a total capacity for 134 GBs, and it says 94 GBs are used up...I'm not sure if that's all computer software taking up space or something else.

I also have some programs that seem to refuse to uninstall from an old video software my dad had...can anyone help me remove it?

Thank you for the help :)

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft® Windows Vista™ Home Basic, Service Pack 2, 32 bit
Processor: Pentium(R) Dual-Core CPU T4200 @ 2.00GHz, x64 Family 6 Model 23 Stepping 10
Processor Count: 2
RAM: 2009 Mb
Graphics Card: Mobile Intel(R) 4 Series Express Chipset Family, 781 Mb
Hard Drives: C: Total - 137586 MB, Free - 37390 MB; E: Total - 14999 MB, Free - 9750 MB;
Motherboard: Dell Inc., 0G848F
Antivirus: Microsoft Security Essentials, Updated and Enabled