Problems internet browsing & some other problems

I have dell inspiron 14 notebook; os windows 8.1
I have been having several problems.

During browsing:
1) the page freezes; or other pages open asking for downloading and installing some
program, and I have to keep on closing that page and clicking on "leave this page".
One unwanted site gives a message that the computer is infected, and that tab cannot even be
closed by task manager. I had to add the desired sites (including Tech support guy) to 'compatability view list' in order to stay on those tabs. .


This has only been happening for a couple of months. I shall appreciate getting help on this problem.
2) I have wireless mouse. Sometimes the mouse just stops working; an intermittent failure of wireless communicqtion.

3) Some programs that I no longer use, cannot be uninstalled.

I shall be thankful for help with these problems.

Thanks,
Preet

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 8.1, 64 bit
Processor: Intel(R) Core(TM) i3-3217U CPU @ 1.80GHz, Intel64 Family 6 Model 58 Stepping 9
Processor Count: 4
RAM: 6010 Mb
Graphics Card: Intel(R) HD Graphics 4000, -1984 Mb
Hard Drives: C: Total - 467769 MB, Free - 426608 MB;
Motherboard: Dell Inc., 01Y1W0
Antivirus: AVG AntiVirus Free Edition 2013, Disabled