Question about linking accounts

I have the first guild wars which I believe is prophecies and I wanted to get back into the game for HoM rewards. My question is if I buy the trilogy from steam can I link that with my old account or is purchasing through steam different than buying a key?

To just connect accounts you need any GW1 account and GW2 account. However connecting them only gives you 3 points. To get more points you need expansion Eye of the North with it's Hall of Monuments.
Eye of the North isn't included in Trilogy, but it's included in Complete collection.

So if I buy the complete collection can I link that to my old GW1 account? I guess I should have been more clear in stating that I already have The first installment.

I don't know how it works with Steam purchases. Any other type of purchase (box or online) gives you a single code, and you can add that code to your existing account to get access to the campaigns you don't already have. You can, for example, add a Trilogy code to an existing account that only has Prophecies, adding Nightfall and Factions to the account. Likewise, a Complete Collection code would add NF, Factions, and EotN.

Perhaps Steam customer support can answer your question? If they offer a code that you can apply to an existing account or have a way to "import" your existing account, then you shouldn't have any problem. If Steam automatically sets up an account for you, then you're stuck.

If you buy GW Complete Collection product, you receive an access key with all three campaigns (Prophecies, Factions and Nightfall) and the Eye of the North expansion. You can apply this key to any existing GW account or make a brand new one.
If you own Prophecies, Factions or Nightfall, you can connect GW1 and GW2 account and get 3 HoM points. If you own Prophecies, Factions or Nightfall and Eye of the North, you can connect GW1 and GW2 account and get up to 50 HoM points.

Steam does not automatically set up a new account. You get a Serial number in steam that you can add to your existing account or create a new account.

Just log into your existing account and add the steam key to it.

Thanks, youre a baller