The variable speed switch on my dremel 395, can I get rep. parts

YES.
DREMEL HAS THAT PART AT ABOUT $2.00 AND SHIPPING ABOUT $2.50.
CALL 1-800-437-3635.

Search the site of TechTastic.ca.Where you can find the Dremel Rotary tool 395.You can ask them how much would it be.

Electrically speaking there are a few items to check.

1) The easiest is to remove the two brush holders screws on each side by the power cord. If one of the screws are loose, or the bushes are worn you will get intermittent or no operation.

2) Second use a volt ohm meter to make sure you have voltage on the two brush connectors inside the brush holders when power is on. If you do then open the unit a check continuity on the motor armature to see if it is open, which will cost $13.37. If you do not have voltage, inspect the power cord and switch.

Some parts can be purchased on the below link.

http://www.ereplacementparts.com/dremel-395-f0130395ca-corded-multitool-parts-c-15440_15456_15474.html

Or contact a dremel service center from the link below.

http://www.dremel.com/en-us/customerservice/ServiceAndRepair/Pages/default.aspx

You'll be hard pressed to find parts...
you can try Dremel Directly http://www.dremel.com/Pages/default.aspx
hope they can get you what you need!

if the motor runs fine ande the drive shaft to the tool just stops turning, look at my previous response

Sounds like a switch or brushes. You can go to Dremel.com and they have a toll free number for their tech services and you can also download a breakdown for this tool.

I would recommend going to Dremel.com and asking their tech section about this. I have one also and mine works fine other than a small amount of heat at the spindle area.

Someone else recently asked the same question and got the following solution;

http://www.fixya.com/support/t1515699-variable_speed_switch_dremel_395_get

It probably can be replaced. For info on this tool call 1-800-437-3635 (Dremel) and speak with customer service about a replacement part. Hope this helps

Definitely not Home Depot. Try googling 'dremel model 395 switch', you'll probably come up with something. If not, there's always dremel themselves. This is a current model so there shouldn't be any real problem getting parts.
Sorry, don't know about installation, but I can tell you most of these dremels are real easy to fix in general, not complicated at all.