Reinstalling OS X Without Erasing the Drive

Boot to the Recovery HD: Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.

Reinstalling OS X Without Erasing the Drive

Repair the Hard Drive and Permissions: Upon startup select Disk Utility from the main menu. Repair the Hard Drive and Permissions as follows.

When the recovery menu appears select Disk Utility and press the Continue button. After Disk Utility loads select the Macintosh HD entry from the the left side list.  Click on the First Aid tab, then click on the Repair Disk button. If Disk Utility reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit Disk Utility and return to the main menu.

Reinstall OS X: Select Reinstall OS X and click on the Continue button.

Note: You will need an active Internet connection. I suggest using Ethernet if possible because it is three times faster than wireless.

Alternatively, see:

Reinstall OS X Without Erasing the Drive

Choose the version you have installed now:

OS X Yosemite- Reinstall OS X

OS X Mavericks- Reinstall OS X

OS X Mountain Lion- Reinstall OS X

OS X Lion- Reinstall Mac OS X

     Note: You will need an active Internet connection. I suggest using Ethernet

                 if possible because it is three times faster than wireless.

If reinstalling the OS X as suggested does not help, then you may have incompatible, bad or a loose RAM module.

For starters exactly which model Mac Mini do you have...?

How to identify Mac mini models - Apple Support

Plus if you upgraded the RAM, what RAM did you buy and use...?

Mac mini: How to remove or install memory - Apple Support

Noting that; all Mac's including Mac Mini's are very picky when it comes to RAM spec's. I only use and recommend vendor's like OWC and Crucial, because they actually test there memory in Mac's.

http://eshop.macsales.com/shop/mac-mini/

http://www.crucial.com/usa/en/apple-memory

I would say it is the memory, Other users have reported similar problem with Corsair Vengeance memory.

Corsair does not even list a 2102 Mini in its Memory Finder table

http://www.corsair.com/en-us/memory-finder

I would return the memory and get memory from a place that specifically says it will work with your model Mini. Places like Crucial or MacSales/OWC

I have the same problem.

Mac Mini mid 2011 2.7 Ghz quad-core i7, 8Gb RAM (aftermarket Crucial 2 x 4Gb), aftermarket Crucial 512 Gb SSD running El Capitan

My Mac is continuously restarting, often without finishing the previous restart cycle.

Steps so far:

Reset PRAM and unplugged-replugged power cord. -> -> No change. Mini keeps restarting.

Disconnected all peripherals, even monitor, keyboard and mouse -> No change. Mini keeps playing reboot chord.

Re-installed original internal hard drive, running Yosemite. -> No change. Mini keeps restarting.

Removed aftermarket (Crucial) RAM and re-installed original RAM chips (2 x 2G). -> No change. Mini keeps restarting.

Re-installed aftermarket Crucial SSD. Reformatted drive and did clean system install. -> -> No change. Mini keeps restarting even during the "new install setup" cycle.

So far, the only way to keep Mini running is by "safe boot", which renders it unusable for most purposes.

Can't afford a new Mac right now. Any suggestions?

Thanks!!

Could be a bad graphics chip. In sae Mode I thin the graphics built into the CPU chip are used.

See:

Mac mini mid 2011 won't boot

2011 mac mini video issue

Thanks!

I looked up the links you mentioned and it looks like a bad video chip shouldn't be ruled out. Sometimes I've been able to keep the Mini running in normal boot for a few minutes. The screen graphics and video files look normal, but one of the linked posts says random rebooting is another symptom. I don't know if that includes constant rebooting + normal picture, but still... it would be terrible, as the Mini's video chip is built-in (mine is AMD Radeon HD 6630).

Will look for used motherboards on eBay...