Sorry for the late reply!
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Here's a few recommendations for you :
- Uninstall both Adobe Flash Player 13 ActiveX and Adobe Flash Player 13 Plugin and install the latest version (14) from here. Do not accept the McAfee Security Scan Plus offer, uncheck the box.;
- Uninstall Java 7 Update 55 and install the latest version (Java 7 Update 65) from here. Do not accept the Ask Toolbar offer during the installation.;
- Uninstall WinRAR 4.00 (64-bit) and install the latest version (WinRAR 5.10) from here;
Also, uninstall the programs that you don't use anymore
Thanks Aura, I've done the first 2.
Any reason to update WinRAR? It's been working really well for me and I'm unsure if it will affect the license.
About uninstalling the unneeded programs, I do that occasionally so that my PC isn't cluttered with un-necessaries. 
And the issue still persists =/
I'm pretty sure the slow down isn't caused by malware/trojan/etc. since the slow down happens only when running several files/programs/etc. simultaneously.
Other possible cause that I could think of is the lack of memory. Could that be it?
I didn't know you had a licence for WinRAR. I don't know if their licence support version upgrade too, you would have to validate with the information they sent you with it. Also, even if it's not needed to update WinRAR, you might have issues with managing .RAR archives that have been created with WinRAR V5+ as it's a modified algorithm that V4 might not support totally.
And how much memory (RAM) do you have in your computer ? What multiple programs are we talking about here ?
The popup requesting license was annoying so I got myself a licence, and Aura up till now I never had a problem with the version I'm using.
I'm curious though, is that previous version really affecting my slow down, and if it is, how so?
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donetao has answered the RAM part, but I'll repeat anyway:
Aura(you): how much memory (RAM) do you have in your computer ?
Skyfer(me): Kingston 4GB (2x 2048 MB) DDR3
Aura(you): What multiple programs are we talking about here ?
Skyfer(me): http://www.geekstogo.com/forum/uploads/monthly_07_2014/post-352411-0-20346800-1406519819.png
http://www.geekstogo.com/forum/uploads/monthly_07_2014/post-352411-0-17370000-1406519866.png
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Donetao, people forget. Most are working in several threads so also get facts confused. A gentle reminder is much better than a smack on the head 
Ztruker, what's your opinion/suggestion on my issue?
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Donetao, people forget. Most are working in several threads so also get facts confused. A gentle reminder is much better than a smack on the head 
Sorry! Didn't mean to be harsh. At 76 years young, believe me I forget a lot of things and I'm always confused.
Thanks for your reply Ztruker!
You're doing a great job here. I think it's great when we all work together to solve members issues.
