In response to your comment, here are a couple of suggestions (N.B. not tested, or even compiled)
foreach (string instanceName in services.GetSubKeyNames())
{
if !instanceName.Contains("MYService") continue;
}
Alternatively you could put the array of subkeynames into a list
keylist
, extract from that list only the MYService entries and iterate through that
var myservices = keylist.Where(t => uids.Contains("MyService"));
foreach (var instanceName in myservices)
{
}