A processor with a LGA775 socket fits to a 775 socket type ?

That's a much older socket type. It was the first LGA (Land Grid Array) that Intel used -- instead of the pins being on the CPU, they're on the motherboard socket. That's a very old design, though, in PC terms -- they replaced it with the LGA 1156, which was replaced by the LGA 1155, which was replaced by the LGA 1150, which is going to be replaced by the LGA 1151.

As for gettiing a new CPU...he might be able to find a used one, but he's limited to maybe a Core 2 Duo or Quad.
 
Well, he wants to buy a Intel Core 2 Duo E5700 3.0Ghz. I just didn`t understand a thing of what you said :)), so, a LGA775 fits with a 775 one?
Seems like he got a MS-7091 motherboard.
 
I hate to break the news but I don't think that CPU will work. If I'm wrong, someone correct me. But the motherboard is the MSI MS-7091. When you search for the MS-7091 manual, the supported CPUs are:

Supports Intel® Pentium 4 Prescott LGA775 processors in LGA775 package.
Supports up to Pentium 4 3XX, 5XX sequence processor or higher speed.

Now, the socket is a 775 and it may work with a Bios update. But I haven't been able to find anything about it.

I did find this.
https://forum-en.msi.com/index.php?topic=107053.0


Dang it logain. This is what happens when people start talking to you at work. Miss out by 8 mins.
 


You know, I`ve found on another site that this CPU fits.

http://www.cpu-world.com/CPUs/Core_2/TYPE-Core%202%20Duo.html

Just look at that and give me your opinion again.
 


The only problem there is that I can`t get that money... I need to sell a lot of things...I`m not a rich boy that has everything :-/
 
You don't have to be rich to get something low end but superior to what you are looking to do.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Pentium G3220 3.0GHz Dual-Core Processor ($64.98 @ SuperBiiz)
Motherboard: ASRock H81M-HDS Micro ATX LGA1150 Motherboard ($49.99 @ Microcenter)
Memory: Kingston 8GB (2 x 4GB) DDR3-1333 Memory ($59.99 @ Mac Mall)
Total: $174.96
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2014-02-06 14:27 EST-0500)
 
Well, thx , I need more 121$ for this :-" , my parents can`t help me actually to get some money for that things, and I`m only 16, so, I think I have to wait till I`ll get a job or something.