Computer keeps crashing all the time.

This past week my computer keeps crashing ALL THE TIME! It had crashed several times as I been trying to write this thread.

It takes forever to get to Google Chrome start page and the same from then on at every single step.
Then it freezes forever. Then a window opens saying "the page is irresponsive" and should I wait or kill it, then more ages to kill it (it freezes again) and then it crashes>closes.

The same everytime I try to save a pic other than to the downloads section it automatically shows when I right-click to "save image". If I try to save it to another folder of my choice (e.g: a pic of my brother to the "family & friends" album instead of said "downloads" folder) it freezes again, goes "irresponsive", HP Support Assistant can't find a solution to the problem, more freezing and then it crashes>closes the page.

What is happening and how do I sort this out? I done every type of scan I have using Avast-AntiVirus, Comodo Firewall and MalwareBytes. I contacted loads of support sites and got no reply from no-one. Pease HELP!

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Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Home Premium, Service Pack 1, 64 bit
Processor: AMD E-300 APU with Radeon(tm) HD Graphics, AMD64 Family 20 Model 2 Stepping 0
Processor Count: 2
RAM: 1642 Mb
Graphics Card: AMD Radeon HD 6310 Graphics, 384 Mb
Hard Drives: C: Total - 286247 MB, Free - 238771 MB; D: Total - 14732 MB, Free - 1639 MB; E: Total - 4055 MB, Free - 5 MB;
Motherboard: Hewlett-Packard, 3577
Antivirus: avast! Antivirus, Updated and Enabled