Advice in hardware upgrade: Processor, Motherboard, RAM

My computer's been running slow the past few weeks. I've run AVG full scans but no viruses or malwares were detected. It's also newly defragmented like last month. It's running nice and normal until my sister got into college this June with a computer course and installed programs into the PC like C++ and Adobe Flash CS3. I don't know if there's any relation but since then I've noticed that it's been running slower. I thought maybe I should upgrade again the hardware to suit the needs of my sister's computer course. I am just not sure if I am on the right track.
I'd like to upgrade my processor to something like i3 or i5 but I don't know if my motherboard which is currently running Pentium(R) Dual-Core CPU E5300 @ 2.60GHz can support it.
My motherboard acc. to some software is ASUSTek Computer INC. P5KPL-AM SE Version X.0x
Or is it just in the RAM? I have 1Gb of RAM. Or is there anything wrong at all with my hardware?
Thanks a lot!

 

This page has your motherboard info http://www.asus.com/Motherboards/Intel_Socket_775/P5KPLAM/#specifications .

That board does not support the i3 or higher CPU series.

Adding another 1Gb of memory would help.

Run CCleaner, especially the registry cleaner section. If you haven't already, run a anti-malware program like MalwareBytes in addition to your AVG scan.

Sam

 

Are those programs currently running as they will slow you down, even with a dual core. I agree, another 1GB ram or two would really help the cause. Otherwise for an ix CPU you'ld also have to change the board and the RAM and perhaps your HDD as everything is SATA these days.

Is she using your administrator account? Perhaps setup an admin account just for her, have her uninstall the two apps. and reinstall on the new user account making sure that it is installed only for her when asked.

Welcome aboard.

 

Windows 7 needs 2 gig minimum RAM for decent running. Are you on 7?

 

Thanks guys! Will take action keeping in mind your advice and opinions