It isn't a case of the "Load avast services only after other system services" not working, but knowing what kind of effect you are likely to get. At best I would say you are likely to get a difference of a second or less, as avast is only waiting for other windows services to load before it does.
This is s troubleshooting option only and would normally be used when avast has problems starting because a service that it requires hasn't loaded.
I also can't understand how a supposed 30 delay then equates to a 2 minute for your system to load, that can't all be down to avast.
You ,mention nothing about the system spec, CPU, RAM, etc. of your laptop, nor do you mention
XP uses much less RAM than win7, so that would be a factor, I have a win7 netbook and that loads very quickly considering the spec - Acer Aspire One, Win7 Starter (32bit), 2GB DDR3 RAM, Intel Atom N255 (1.5GHz dual core) CPU.
But I'm strict about what I allow to run on boot, so that is an area you need to look at. Many applications want to start on boot when there really is no need, media players are typical of this and are only needed when a media file is run (and that opens it anyway).
New laptops generally come with a lot of pre-installed cr4p and often an anti-virus, that has to be uninstalled ?
There is a possibly that additional removal tools to ensure it is completely gone, or there may be conflicts.