tiny flies in compost

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I did my usual hyacinths-for-the-house this year but have been plagued by tiny flies emerging from the (garden centre) compost.  I'd like to start some salad leaves indoors on the windowsill but I can't face the kitchen being filled with these things. Can I sterilize small quantities in the microwave, will this destroy them?  I don't want to spray, and I don't want to buy more compost yet.

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[Robert_Brenchley]

The microwave will do, but I'm not sure how long to leave it. I used to put it in the oven till it steamed. The process is a smelly one. Alternatively, you could use Jeyes to sterilise it, but it has to be left in an open container for six weeks to allow it to evaporate.

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Thanks for that, Robert, I might try the oven steaming - OH has no sense of smell and I can put up with it in a good cause....

[ipt8]

I suggest you complain to the garden centre, even if it is just to let them know of the problem. Many composts are now having municipal wastes added in and I bet that is the cause. Whatever the reason I would say it has not been composted properly for flies to appear.

[tonybloke]

http://www.bbc.co.uk/gardening/advice/pests_and_diseases/nonflash_index.shtml?black_fungus_gnats

all you need to know about fungus gnats / scariad flies. ;)

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Thank you Tonybloke, that's a great link and I reckon black fungus gnats are the culprits.
ipt8, I didn't think to mention it to the garden centre but will certainly do so.
I've bought some new compost to start off my tender stuff indoors, once I've cleared the house of these little horrors.....