I regret using Kaspersky on a XP PC with 996mb of ram..

Like i had to switch to classic mode and uncheck almost all of those things in the performance...Soon im planning upgrading it to 2 gb then i will be able to switch luna since i used kasperaky on a 2gb pc and it was smoth

 

I'm not certain as to whether or not older versions of Kaspersky still get virus definition updates the same way older Avast versions do, but if you can find an old Kaspersky version that still gets updates then that may be your best chance to have a possibility for good performance with Kaspersky. I was never a big Kaspersky fan even in the old days (when I first tried Avast 4.8 I didn't give ANY other antivirus a second [or even first] thought), but if you've got enough RAM and a fast-enough processor then it is a good option.

I'm not sure what specific model of PC you're running (I remember you telling me it was a Pentium 4 HT), but if your motherboard can take up to 4GB of RAM then I would upgrade all the way if you can afford to max it out. My DC5000 SFF was upgraded up to the maximum 4GB (from the 512MB it originally came with)--when you have a P4 without hyper-threading (mine is a 2.8GHz Prescott) it makes a huge difference in performance, especially with modern web browsers (my current [finalized] setup is Firefox 52.9.1ESR for most sites and Chromium 49 for others--I'm able to use both in tandem with surprisingly good performance for my daily tasks).

A lot of people switch to classic mode if they find their PC is running slow, which is understandable. I've always preferred to use it as the default, since not only is it faster but it gives you more screen real estate to work with, and brings back that old-school Windows 9x look. I always use the Windows Classic theme and eliminate the gradients on the bars so it feels more like Win95.