This isn't the right newsgroup to be asking your question... but
T stands for TrueType fonts.
O stands for OpenType fonts.
If you want to know what each of those are, do an internet search for "TrueType" and "OpenType".

Signature
Greg Collins [InfoPath MVP]
Visit http://www.InfoPathDev.com
On my control panel in fonts the majority are T's then Arial, Courier, and a
few others are O's is this the reason I am having trouble and things are in
italics