[SOLVED] 7 year old pc needs some love

[pandasmash]

hi guys and gals. have an issue with my pc shutting down. replaced the thermal paste as it all dried out. pc lasted 3 days wth no problems (only lasted 20 minutes beofre i replaced the paste). downloaded wolfstein 2 and it died after 1hr of gameplay. so i decided it was time to replace some parts. namely cpu and heatsink as assuming these are causing the issues.
but any suggestions on other changes too would be great. but not planning spening more than £500 total.
current specs:-
NZXT Switch 810
windows 7 pro 64-bit
i5-3570K
Asus P8Z77-V LX
Corsair 8GB 1600MHz CL9 DDR3 Vengeance Memory Two Module Kit
Corsair TX750 V2 750w psu
GIGABYTE GeForce GTX 1060 Windforce OC 6gb
Corsair H100
Agility 3 120GB SSD and some big storage hdd's

would like to increase the ram. best to get another two 4gb sticks or to replace what i have?
any suggestions on cpu upgrade? never bought second hand but thought ebay may be worth looking at?
what heatsink do you suggest?

anything i have missed apologies. and many thanks in advance you guys are great.

 

[NightHawkRMX]

Check CPU temps during games using a program like hwinfo to see if the unexpected shutdowns are caused by thermal issues.
https://www.cpuid.com/softwares/hwmonitor.html

Mixing ram doesn't usually go well. What is your budget for a CPU upgrade? Often times old I7s cost enough that it makes more sense to purchase a superior modern Ryzen 5 or I5 plus other platform components.

 

[pandasmash]

Check CPU temps during games using a program like hwinfo to see if the unexpected shutdowns are caused by thermal issues.
https://www.cpuid.com/softwares/hwmonitor.html

Mixing ram doesn't usually go well. What is your budget for a CPU upgrade? Often times old I7s cost enough that it makes more sense to purchase a superior modern Ryzen 5 or I5 plus other platform components.

will install that and have a look thanks.
ideally spend as little as possible but around £300. dont play enough any more so cant justify spening too much or the mrs will kill me

 

[Vic 40]

Maybe paste on the chipset is dry as well and might need replacement.

That psu is also pretty old and maybe running on it's last legs.

You also might still be able to upgrade to W10 for free, something i would do.

 

[pandasmash]

Maybe paste on the chipset is dry as well and might need replacement.

That psu is also pretty old and maybe running on it's last legs.

You also might still be able to upgrade to W10 for free, something i would do.

what psu do you reccommend? corsair tx 750m?

 

[Vic 40]

Not that i don't want you to spend money,but did you check cpu temps as asked?

The TX750M is a good psu,you could get by with the 550watt version though or for some extra watts the 650watt one.

What budget for a psu and what country are you in?