About six months ago, I purchased a new Dell Optiplex 9020 SFF and installed a Gigabyte GT 1030 low profile graphics card and upgraded the PSU to a 315w model to support the card. 

Since then, everything has been running fine, with optimal performance. 

Last week, I started running into this issue with the PC boot. I'll turn on the power strip and hit the power button. But instead of starting up, the LED blinks - 2 times, then a pause, then another time. I looked this up in the manual and apparently it indicates a "system board failure". However, I've found that all I have to do to start it up is unplug one or more of three USB connections (one audio input, a drawing tablet, and a webcam) from the front of the chasis, and it will start up and run fine. However, if I start it up the next day, I will have to do the same thing.

Does anyone have an explanation for this? Should I be concerned? Or is this just an error that I will have to work around. 

Thanks!

Eben