I've reordered the IP addresses to make it easier to parse in my head.
It's unfortunate that your copy and paste truncated some of the lines, but I think we can figure out what is necessary. BTW, your configuration shows 6 IPs on ether1. There may have been a typo in your first post which said 5 IPs
add address=y.y.y.36/24 comment="Internet Connection" inte(erface=ether1)
add address=y.y.y.37/24 comment="Chris Sparks" interface=e(ther1)
add address=y.y.y.38/24 comment="Chris Sparks" interface=e(ther1)
add address=y.y.y.39/24 comment=Claude interface=ether1
add address=y.y.y.40/24 disabled=yes interface=ether1
add address=y.y.y.41/24 disabled=yes interface=ether1
add address=10.254.254.1/24 interface="LAN Bridge"
add address=192.168.88.2/24 interface=ether7
add address=10.254.250.1/24 comment="BH to MSWT" interface=ethe
add address=10.1.3.1/24 comment="UbiquitiOmni port12" interface
add address=192.168.3.1/24 comment="UbiquitiOmni port12" interf
add address=192.168.1.1/24 interface=ether4
add address=192.168.254.1/24 interface=ether11
Personally, I would set the prefix length of y.y.y.37-41 to /32; leaving y.y.y.36 with its /24 prefix length. It may not be required on MikroTik, but it probably won't hurt. It has been required on some other systems I have used over the years.
Do you really not have any /ip firewall filter or /ip firewall mangle or /ip firewall address-list in your configuration?
I've reordered the two disabled NAT dst-nat rules to after the masquarade rule to make it easier for my brain to deal with. I also removed the line wrap.
/ip firewall nat
add action=dst-nat chain=dstnat comment=RADIUS dst-address=y.y.y.36 protocol=udp to-addresses=10.254.254.10 to-ports=1810-1816
add action=dst-nat chain=dstnat comment="Server DST-NAT" dst-address=y.y.y.36 protocol=tcp to-addresses=10.1.2.15 to-ports=3389
add action=dst-nat chain=dstnat comment="E and W Sharepoint" dst-address=y.y.y.39 protocol=tcp to-addresses=10.1.2.13 to-ports=80
add action=dst-nat chain=dstnat comment="Bobs Paint and Body RDP" dst-address=y.y.y.39 protocol=tcp to-addresses=10.1.2.15 to-ports=3389
add action=masquerade chain=srcnat comment="Masquerade all traffic" out-interface=ether1
(all disabled rules below here)
add action=src-nat chain=srcnat comment="Chris Sparks SRC-Nat" disabled=yes src-address=192.168.3.21 to-addresses=y.y.y.38
add action=dst-nat chain=dstnat disabled=yes dst-address=y.y.y.38 to-addresses=192.168.3.21
add action=src-nat chain=srcnat comment="Server SRC-Nat" disabled=yes src-address=10.254.254.10 to-addresses=y.y.y.36
add action=src-nat chain=srcnat comment="Sharon Hoppe" disabled=yes src-address=10.1.2.3 to-addresses=y.y.y.38
add action=dst-nat chain=dstnat disabled=yes dst-address=y.y.y.38 to-addresses=10.1.2.3
add action=dst-nat chain=dstnat comment=Claude disabled=yes dst-address=y.y.y.39 to-addresses=10.2.0.6
add action=src-nat chain=srcnat disabled=yes src-address=10.1.2.6 to-addresses=y.y.y.39
From where are you pinging; from outside ether1, or from behind one of the other interfaces on the RB1100?
I don't see anything "wrong" with the config you gave us. But if you didn't give us the filter/masquerade/address-list parts, we are still blind.
Does "/system routerboard print" and / or "/system routerboard settings print" give you any blank fields or errors? My thinking is that it *might* be possible that the firmware was corrupted so didn't load and you are running on top of the backup bootloader firmware which could be really old and buggy. I don't *know* that would cause any issues. That is just me making a wild guess after not seeing a problem with the config you showed us.
Another wild idea: I also just want to confirm that the prefix length is supposed to be /24 rather than /29. It is acceptable to do it either way, but if it is supposed be a /29, your default gateway would probably be y.y.y.33 and you would be using the five IPs from y.y.y.34-38. Having the wrong prefix length and using some of the wrong IPs might cause some issues like you are reporting. The upstreams gear might have previously been configured more ambiguously and permitted the incorrect configuration on your end.
You are probably correct, but while I am grasping at straws, I thought I would try for more than one. :D